Optimization of heat transfer properties of the directional solidification furnace by modifying heat exchanger blocks

Abstract

The grown mc-Silicon crystal suffers from several defects like von Mises stress, dislocation, higher temperature gradient and impurities. We carried out transient global simulations of growth process in first generation directional solidification (G1-DS) furnace with three different Heat Exchanger Blocks (HEB) for studying the heat transfer process. The simulation has been made for G1-DS without grooved-HEB (conventional furnace); G1-DS with grooved-HEB with groove filled with the lower density graphite (LDG) block (case-1); G1-DS with grooved-HEB with side gap filled with the HDG block (case-2); G1-DS with grooved-HEB with groove filled with the LDG and side gap filled with HDG (case-3). The results were compared and analysed which confirms that case-3 has lower temperature gradient in axial-radial directions, lower dislocation density and lower von Mises stress in the mc-Silicon ingot at end of the crystal growth process. It is concluded from the comparison results with different modification that the minimum von Mises stress can prevent the multiplication of dislocations and case-3 gives good quality ingots. Some basic heat transfer properties are understood in the G1-DS furnace through the simulation results.